Effects of feed restriction on production performance of replacement pullets

Two experiments were conducted to evaluate the effects of feed restriction on production performance of egg production pullets. In Experiment 1, two brown-egg strains (A and B) were subjected to full feeding, a restricted duration of feeding program, and a quantitative feed restriction program. Two White Leghorn strains (C and D) were subjected to full feeding and restricted duration of feeding only. For Experiment 2, only strains B and D were used and an additional restricted duration of feeding program was studied. Pullets were maintained on these programs to 20 weeks of age. Production data were collected to 66 and 62 weeks of age for Experiments 1 and 2, respectively. Restricted duration of feeding was found to depress body weight by 2 to 3%, and quantitative feed restriction depressed body weight by 5% with feed intake depressed by the same magnitudes. Feed restriction at these levels had no significant effects on hen-day or hen-housed egg production, egg weight, egg mass, or egg grades. Net egg income over feed cost was significantly improved by feed restriction in Experiment 2. Pullets on quantitative restriction produced the greatest returns. This was due to increased numbers of large eggs and the decrease in rearing feed consumption. Feed restriction had no effect on mortality or sexual maturity. Feed consumption, body weight, egg weight, and economic returns were higher for the heavy strain of pullets. Mortality was highest within the light strains.

The effects of dietary protein levels, ahemeral light and dark cycles, and intermittent photoperiods on the performance of chicken broiler parent genotypes

Two experiments were undertaken to estimate the effect of: 1) two dietary protein levels (13.6 and 15.4%) in breeder diets fed to commercial meat parent genotypes; and 2) 6 photoperiods involving both 24-hr and 27-hr (ahemeral) day cycles with single stage and intermittent lighting for birds housed in floor pens. It was concluded that the 13.6% protein breeder diet, which provided from 14.8 to 20.9 g of protein per bird per day and from 301 to 425 kcal of ME per bird per day, was adequate to support optimum performance. The ahemeral light treatment 14L:13D used from 168 to 448 days had a depressing effect on egg production and feed efficiency compared with the conventional 24-hr day cycle with 14L:10D light treatment. The 14L:13D treatment, however, did result in increased egg size and improved shell strength. The intermittent light treatments, whether ahemeral or 24-hr cycle, resulted in improved egg weight and shell strength. The ahemeral intermittent treatment (10L:12D:2L:3D) had the effect of depressing fertility and hatchability, whereas the 24-hr intermittent photoperiod (10L:9D:2L:3D) resulted in fertility and hatchability equal to or better than other treatment. It was concluded that the 24-hr intermittent light treatment (10L:9D:2L:3D) supported performance which was equal to or better than other light treatments including the 27-hr ahemeral day cycles. Furthermore, ahemeral day cycles resulted in large numbers of eggs laid on the floor (Ca. 50%. First and second order interactions appeared to be of minor importance.